This invention relates to means for preheating air that is ultimately raised to a higher operating temperature for use in an industrial processing oven and in particular with means to induce a confined air current over a heated surface to effect a heat exchange between the heated surface and the air current.
There are classes of industrial processing ovens which are exceptionally large and use enormous amounts of fuel to heat air to relatively high operating temperatures for use, within the oven. Some of these ovens have cross-sectional areas at least as large as 8 feet by 14 feet and lengths which may exceed 75 feet. The walls of these ovens are typically manufactured in sections or panels which are joined together to form the oven enclosure. Each section typically consists of two spaced apart metal plates with insulation inserted between the plates. Even though the oven walls are insulated, large amounts of heat are lost through the oven walls. This wasted heat raises the temperature of the outer oven wall to undesirably high levels and can create a safety hazard to operating personnel. In addition, the work area in the vicinity of the oven can become oppressively hot making it uncomfortable for personnel to work in the area. Even more importantly, the heat loss, in effect, represents uneconomic utilization of fuel.
Accordingly, it is an object of this invention to provide an industrial oven with means to induce and establish a confined air current in a plurality of air passages to effect a heat exchange between the heated outer surface of an industrial processing oven and the air current to thereby preheat ambient air to higher temperatures. It is a further object of this invention to provide said oven with a false outer skin which is spaced from the heated outer oven wall to thereby provide said confined air passages. It is a further object of this invention to provide an industrial oven which may be safely touched, which preheats ambient air to thereby reduce fuel consumption, which permits reduced use of oven insulation, which is prefabricated in sections to reduce assembly time and which utilizes otherwise lost heat. These and other objects are achieved as follows.